[aeontech]

We already have redundancy - since git is distributed, Github going down does not impact our development or deployment.

Github provides a great user experience for discussion and managing branches/pull requests. Issue tracking is usable enough that some companies find it sufficient.

The cost is literally unnoticeable for pretty much any company.

"Many" service outages is an exaggeration, I think. It's just selection bias - if you don't use github, and the only time you hear about it is when they get attacked, you'll have an impression that they are under constant attack.

For the companies I have worked at, in short, there was no downside, and decent upside to using it.